ORIGINAL: erazz
You're saying you want more thrust in smaller package, right? Even if the fuel draw is horrible?
Very generally a 40# engine in a 30# case will draw fuel like a 50# engine.
Well.. A 25lb# engine size in a JL L-39 (Example 40#thrust for a L-39 or a S/M F-18c ) will put your throttle setting above haft the whole flight. But with a bigger engine your throttle just above idle & better fuel consumption.
P.s In my opinion